1. Technical Field
The present invention relates to a piezoelectric element and the like.
2. Related Art
Biological information is measured by using an ultrasonic probe and an ultrasonic measurement device using a piezoelectric element as a transducer for ultrasonic transmitting and receiving, and vascular functions are evaluated or vascular diseases are determined. For example, JP-A-2008-173177, for example, discloses an ultrasonic probe and an ultrasonic measurement device which automatically detect vascular walls by using reflected wave signal intensity from biological tissues obtained by processing amplitude information of received ultrasonic waves and a moving velocity of biological tissues obtained by processing phase information of received ultrasonic waves.
A piezoelectric element used in the ultrasonic probe and the ultrasonic measurement device is prepared by laminating a piezoelectric body on a vibrating plate on a thin film, as disclosed in JP-A-60-206315, for example.
It was found that a single crystal silicon wafer used in the manufacturing of a general piezoelectric element has anisotropy in a Young's modulus or a Poisson's ratio, in accordance with plane orientation. However, in a manufacturing method of a piezoelectric element of the related art, a plurality of elements were simply spread on a single crystal silicon wafer, without particularly considering for anisotropy, patterned, and cut out to prepare a piezoelectric element. That is, even piezoelectric elements prepared by cutting out the same silicon wafer, vibrating properties of each piezoelectric element were different from each other and variations in properties of the piezoelectric elements occurred.